1. Field of the Invention
The present invention relates to a developing device to be used in an electrophotographic copying machine or, an electrostatic recording apparatus, and more particularly to a means for driving a developer stirring blade in the developing device.
2. Description of the Prior Art
In a dry type developing device, as is generally known, a stirring blade is built therein for the purposes of frictionally charging a developer stored therein and of uniformly mixing recovered and/or replenishment toner with other developer.
Heretofore, the structures of the stirring blades with the aforesaid purposes have so far been improved in various ways to uniformly mix up the developer within a short period of time by whatever configuration or structure the stirring blade has. In other words, the conventional stirring blades have been devised so as to tilt in the reverse direction or to alternately change the direction right and left, all of which has been driven to revolve in one direction at a constant speed. Part of the developer is rapidly stirred but there is caused an area where no stirring has been carried into effect locally, and therefore it takes a long time until the developer is satisfactorily mixed up overall. Recently in particular, because of the tendencies to accelerate the copying speeds and to stir the developer insufficiently, other problems have arisen such as an image unevenness.